Antifungal lactic acid bacteria as biopreservatives

Anti-fungal effects of lactic acid bacteria from pickles on the growth and sterigmatocystin production of Aspergillus versicolor

Sterigmatocystin (STC) is an emerging mycotoxin that poses a significant threat to the food security of cereal crops. To mitigate STC contamination in maize, this study employed selected lactic acid bacteria as biocontrol agents against Aspergillus versicolor, evaluating their biocontrol potential and analyzing the underlying mechanisms. Lactiplantibacillus plantarum HJ10, isolated from pickle, exhibited substantial in vitro antifungal activity and passed safety assessments, including antibiotic resistance and hemolysis tests. In vivo experiments demonstrated that L. plantarum HJ10 significantly reduced the contents of A. versicolor and STC in maize (both >84 %). The impact of heat, enzymes, alkali, and other treatments on the antifungal activity of cell-free supernatant (CFS) was investigated. Integrated ultra-high-performance liquid chromatography (UPLC) and gas chromatography-mass spectrometry (GC-MS) analysis revealed that lactic acid, acetic acid, and formic acid are the key substances responsible for the in vitro antifungal activity of L. plantarum HJ10. These metabolites induced mold apoptosis by disrupting cell wall structure, increasing cell membrane fluidity, reducing enzyme activities, and disrupting energy metabolism. However, in vivo antagonism by L. plantarum HJ10 primarily occurs through organic acid production and competition for growth space and nutrients. This study highlights the potential of L. plantarum HJ10 in reducing A. versicolor and STC contamination in maize.

A Snapshot, Using a Multi-Omic Approach, of the Metabolic Cross-Talk and the Dynamics of the Resident Microbiota in Ripening Cheese Inoculated with Listeria innocua

Raw milk cheeses harbor complex microbial communities. Some of these microorganisms are technologically essential, but undesirable microorganisms can also be present. While most of the microbial dynamics and cross-talking studies involving interaction between food-derived bacteria have been carried out on agar plates in laboratory-controlled conditions, the present study evaluated the modulation of the resident microbiota and the changes of metabolite production directly in ripening raw milk cheese inoculated with Listeria innocua strains. Using a proxy of the pathogenic Listeria monocytogenes, we aimed to establish the key microbiota players and chemical signals that characterize Latteria raw milk cheese over 60 days of ripening time. The microbiota of both the control and Listeria-inoculated cheeses was analyzed using 16S rRNA targeted amplicon sequencing, while direct analysis in real time mass spectrometry (DART-HRMS) was applied to investigate the differences in the metabolic profiles of the cheeses. The diversity analysis showed the same microbial diversity trend in both the control cheese and the inoculated cheese, while the taxonomic analysis highlighted the most representative genera of bacteria in both the control and inoculated cheese: Lactobacillus and Streptococcus. On the other hand, the metabolic fingerprints revealed that the complex interactions between resident microbiota and L. innocua were governed by continuously changing chemical signals. Changes in the amounts of small organic acids, hydroxyl fatty acids, and antimicrobial compounds, including pyroglutamic acid, hydroxy-isocaproic acid, malic acid, phenyllactic acid, and lactic acid, were observed over time in the L. innocua-inoculated cheese. In cheese that was inoculated with L. innocua, Streptococcus was significantly correlated with the volatile compounds carboxylbenzaldheyde and cyclohexanecarboxylic acid, while Lactobacillus was positively correlated with some volatile and flavor compounds (cyclohexanecarboxylic acid, pyroxidal acid, aminobenzoic acid, and vanillic acid). Therefore, we determined the metabolic markers that characterize a raw milk cheese inoculated with L. innocua, the changes in these markers with the ripening time, and the positive correlation of flavor and volatile compounds with the resident microbiota. This multi-omics approach could suggest innovative food safety strategies based on the enhanced management of undesirable microorganisms by means of strain selection in raw matrices and the addition of specific antimicrobial metabolites to prevent the growth of undesirable microorganisms.

Antifungal mechanisms investigation of lactic acid bacteria against Aspergillus flavus: through combining microbial metabolomics and co-culture system

AIMS

To develop antifungal lactic acid bacteria (LAB) and investigate their antifungal mechanisms against Aspergillus flavus in aflatoxin (AF) production.

METHODS AND RESULTS

We isolated 179 LABs from cereal-based fermentation starters and investigated their antifungal mechanism against A. flavus through liquid chromatography-mass spectrometry and co-culture analysis techniques. Of the 179 isolates, antifungal activity was identified in Pediococcus pentosaceus, Lactobacillus crustorum, and Weissella paramesenteroides. These LABs reduced AF concentration by (i) inhibiting mycelial growth, (ii) binding AF to the cell wall, and (iii) producing antifungal compounds. Species-specific activities were also observed, with P. pentosaceus inhibiting AF production and W. paramesenteroides showing AF B1 binding activity. In addition, crucial extracellular metabolites for selecting antifungal LAB were involved in the 2',3'-cAMP-adenosine and nucleoside pathways.

CONCLUSIONS

This study demonstrates that P. pentosaceus, L. crustorum, and W. paramesenteroides are key LAB strains with distinct antifungal mechanisms against A. flavus, suggesting their potential as biological agents to reduce AF in food materials.

Bacillus velezensis RC218 and emerging biocontrol agents against Fusarium graminearum and Fusarium poae in barley: in vitro, greenhouse and field conditions

Fusarium head blight (FHB) is one of the most common diseases in Argentina, affecting the quality and yield of barley grains. Fusarium graminearum sensu stricto (ss) and Fusarium poae are causal agents of FHB and potential sources of mycotoxin contamination in barley. Conventional management strategies do not lead to a complete control of FHB; therefore, biological control emerges as an eco-friendly alternative in the integrated management of the disease. In the present work, Bacillus velezensis, Bacillus inaquosorum, Bacillus nakamurai and Lactobacillus plantarum were evaluated as potential biocontrol agents against F. graminearum ss and F. poae on barley-based media. Bacillus velezensis RC218 was selected to carry out greenhouse and field trials in order to reduce FHB and mycotoxin accumulation. This strain was able to control growth of both Fusarium species and reduced deoxynivalenol (DON) and nivalenol (NIV) production by 66 % and 79 %, respectively. Bacillus inaquosorum and B. nakamurai were more effective in controlling F. poae growth, and the mean levels of reduction in DON accumulation were 50 and 38 %, and 93 and 26 % for NIV, respectively. Lactobacillus plantarum showed variable biocontrol capacity depending on the strain, with no significant mycotoxin reduction. The biocontrol on incidence and severity of FHB in the greenhouse and field trials was effective, being more efficient against F. graminearum ss and DON accumulation than against F. poae and NIV occurrence. This study provides valuable data for the development of an efficient tool based on biocontrol agents to prevent FHB-producing Fusarium species development and mycotoxin occurrence in barley, contributing to food safety.

Inhibiting pathogenicity of vaginal Candida albicans by lactic acid bacteria and MS analysis of their extracellular compounds

Maintaining healthy vaginal microflora post-puberty is critical. In this study we explore the potential of vaginal lactic acid bacteria (LAB) and their extracellular metabolites against the pathogenicity of Candida albicans. The probiotic culture free supernatant (PCFS) from Lactobacillus crispatus, L. gasseri, and L. vaginalis exhibit an inhibitory effect on budding, hyphae, and biofilm formation of C. albicans. LGPCFS manifested the best potential among the LAB PCFS, inhibiting budding for 24 h and restricting hyphae formation post-stimulation. LGPCFS also pre-eminently inhibited biofilm formation. Furthermore, L. gasseri itself grew under RPMI 1640 stimulation suppressing the biofilm formation of C. albicans. The PCFS from the LAB downregulated the hyphal genes of C. albicans, inhibiting the yeast transformation to fungi. Hyphal cell wall proteins HWP1, ALS3, ECE1, and HYR1 and transcription factors BCR1 and CPH1 were downregulated by the metabolites from LAB. Finally, the extracellular metabolome of the LAB was studied by LC-MS/MS analysis. L.gasseri produced the highest antifungal compounds and antibiotics, supporting its best activity against C. albicans. Vaginal LAB and their extracellular metabolites perpetuate C. albicans at an avirulent state. The metabolites produced by these LAB in vitro have been identified, and can be further exploited as a preventive measure against vaginal candidiasis.

Biopreservative and Anti-Mycotoxigenic Potentials of Lactobacillus paracasei MG847589 and Its Bacteriocin in Soft White Cheese

Probiotics and their bacteriocins have increasingly attracted interest for their use as safe food preservatives. This study aimed to produce soft white cheese fortified with Lacticaseibacillus MG847589 (Lb. paracasei MG847589) and/or its bacteriocin; cheese with Lacticaseibacillus (CP), cheese with bacteriocin (CB), and cheese with both Lacticaseibacillus and bacteriocin (CPB) were compared to control cheese (CS) to evaluate their biopreservative and anti-mycotoxigenic potentials for prolonged shelf life and safe food applications. The effects of these fortifications on physiochemical, microbial, texture, microstructure, and sensory properties were studied. Fortification with Lacticaseibacillus (CP) increased acidity (0.61%) and microbial counts, which may make the microstructure porous, while CPB showed intact microstructure. The CPB showed the highest hardness value (3988.03 g), while the lowest was observed with CB (2525.73 g). Consequently, the sensory assessment reflected the panelists' preference for CPB, which gained higher scores than the control (CS). Fortification with Lb. paracasei MG847589 and bacteriocin (CPB) showed inhibition effects against S. aureus from 6.52 log10 CFU/g at time zero to 2.10 log10 CFU/g at the end of storage, A. parasiticus (from 5.06 to 3.03 log10 CFU/g), and P. chrysogenum counts (from 5.11 to 2.86 log10 CFU/g). Additionally, CPB showed an anti-mycotoxigenic effect against aflatoxins AFB1 and AFM1, causing them to be decreased (69.63 ± 0.44% and 71.38 ± 0.75%, respectively). These potentials can extend shelf life and pave the way for more suggested food applications of safe food production by fortification with both Lb. paracasei MG847589 and its bacteriocin as biopreservatives and anti-mycotoxigenic.

Comprehensive review of clean-label antimicrobials used in dairy products

Consumers expect safe, healthy, natural, and sustainable food. Within the food industry, ingredient use is changing due to these consumer demands. While no single agreed-upon definition of clean label exists, a "clean label" in the context of food refers to a product that has a simplified and transparent ingredient list, with easily recognizable and commonly understood components to the general public. Clean-label products necessitate and foster a heightened level of transparency between companies and consumers. Dairy products are vulnerable to being contaminated by both pathogens and spoilage microorganisms. These microorganisms can be effectively controlled by replacing conventional antimicrobials with clean-label ingredients such as protective cultures or bacterial/fungal fermentates. This review summarizes the perspectives of consumers and the food industry regarding the definition of "clean label," and the current and potential future use of clean-label antimicrobials in dairy products. A key goal of this review is to make the concept of clean-label antimicrobial agents better understood by both manufacturers and researchers.

A Novel Strategy for Whole-Cell Biotransformation Enabling Simultaneous l-Phenyllactic Acid Production and Coenzyme Regeneration

l-Phenyllactic acid (l-PLA) is a small molecular organic acid that exhibits a powerful capacity for inhibition against foodborne pathogens. In this work, we developed a new cost-effective and environmentally friendly process for the biosynthesis of l-PLA. This strategy designed a novel whole-cell biotransformation system employing two heterologous enzymes, namely, phenylalanine dehydrogenase (PheDH) and l-hydroxyisocaproate dehydrogenase (l-HicDH). The novelty of this strategy lies in the first-time utilization of these two enzymes, which not only enables cascade catalysis for the production of l-PLA but also facilitates the regeneration of the coenzymes (NAD+/NADH) using only two enzymes rather than introducing more heterologous enzymes to the system. Consequently, this strategy can effectively simplify the biosynthesis process of l-PLA and minimize production costs. The initial l-PLA yield using this process achieved 2.53 ± 0.07 g/L. Furthermore, through meticulous optimization of the parameters for inducible enzyme expression and l-PLA biosynthesis, the l-PLA yield was successfully increased to 4.68 ± 0.04 g/L with a yield rate of 64.54 ± 0.29%. Moreover, this novel strategy is versatile in the biosynthesis of other organic acids, which can be achieved by easily modulating the combinations of substrates and enzymes.

Inhibition of Aspergillus carbonarius growth and Ochratoxin A production using lactic acid bacteria cultivated in an optimized medium

The Gram-positive bacteria lactic acid bacteria (LAB) are used in the food industry but are also known for inhibiting certain food spoilage microorganisms, especially fungi. Sources of nitrogen (N) for culture media are generally organic and expensive. Many attempts have been made to formulate economical culture media with alternative N sources obtained from agricultural and industrial byproducts. This study describes the design and optimization of an inexpensive culture medium for Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) MZ809351 strain B31. The culture medium was optimized using statistical experimental designs to identify the factors with the most significant effects on biomass concentration to reduce the overall cost, aiming to obtain a biomass concentration similar to that obtained with the reference LAB culture medium (de Man, Rogosa and Sharpe; MRS). Sodium acetate and magnesium sulfate were the most significant factors (p < 0.005), and their contents were reduced by 22 % and 40 %, respectively, without affecting biomass concentration. Malt germ extract (MGE) was used as an alternative nitrogen source to replace meat extract (ME) and proteose peptone (PP). Through these experiments, the composition of a culture medium that is less expensive than MRS broth was defined, which produced a biomass concentration (3.8 g/L) similar to that obtained with MRS medium. The inhibitory effects of two LAB strains isolated from the Ivory Coast and Mexico on the growth and production of ochratoxin A (OTA) in an ochratoxigenic fungus was tested. The minimum cellular concentration of the LAB to prevent the development of Aspergillus carbonarius Ac 089 and the production of OTA was determined in a model assay in Petri dishes. The conditions to inhibit the germination of A. carbonarius Ac 089 and the production of OTA were found. Using the optimized medium and a ratio of 2 × 104 LAB/spore (1 × 108 CFU/mL) strain B7 (L. plantarum MZ809351) and 2 × 103 LAB/spore (1 × 107 CFU/mL) strain B31 (L. plantarum MN922335) completely inhibited the growth of the fungus. A ratio of 2 × 105 LAB/spore (1 × 109 CFU/mL) was required to inhibit OTA production with strains B7 and B31. This study indicates the potential of cultivating LAB in an optimized and inexpensive culture medium for use as a biological control agent against ochratoxigenic fungi in food.

Whole-genome sequencing and antimicrobial potential of bacteria isolated from Polish honey

The aim of this study was the whole-genome analysis and assessment of the antimicrobial potential of bacterial isolates from honey harvested in one geographical location-the north of Poland. In total, 132 strains were derived from three honey samples, and the antimicrobial activity of CFAM (cell-free after-culture medium) was used as a criterion for strain selection and detailed genomic investigation. Two of the tested isolates (SZA14 and SZA16) were classified as Bacillus paralicheniformis, and one isolate (SZB3) as Bacillus subtilis based on their ANI and phylogenetic analysis relatedness. The isolates SZA14 and SZA16 were harvested from the same honey sample with a nucleotide identity of 98.96%. All three isolates have been found to be potential producers of different antimicrobial compounds. The secondary metabolite genome mining pipeline (antiSMASH) identified 14 gene cluster coding for non-ribosomal peptide synthetases (NRPs), polyketide synthases (PKSs), and ribosomally synthesized and post-translationally modified peptides (RiPPs) that are potential sources of novel antibacterials. The BAGEL4 analysis revealed the presence of nine putative gene clusters of interest in the isolates SZA14 and SZA16 (including the presence of six similar clusters present in both isolates, coding for the production of enterocin Nkr-5-3B, haloduracin-alpha, sonorensin, bottromycin, comX2, and lasso peptide), and four in B. subtilis isolate SZB3 (competence factor, sporulation-killing factor, subtilosin A, and sactipeptides). The outcomes of this study confirm that honey-derived Bacillus spp. strains can be considered potential producers of a broad spectrum of antimicrobial agents. KEY POINTS: • Bacteria of the genus Bacillus are an important component of honey microbiota. • Honey-derived Bacillus spp. strains are potential producers of new antimicrobials.

An edible coating utilizing Malva sylvestris seed polysaccharide mucilage and postbiotic from Saccharomyces cerevisiae var. boulardii for the preservation of lamb meat

Currently, microbial bioactive substances (postbiotics) are considered a promising tool for achieving customer demand for natural preservatives. This study aimed to investigate the effectiveness of an edible coating developed by Malva sylvestris seed polysaccharide mucilage (MSM) and postbiotics from Saccharomyces cerevisiae var. boulardii ATCC MYA-796 (PSB) for the preservation of lamb meat. PSB were synthesized, and a gas chromatograph connected to a mass spectrometer and a Fourier transform infrared spectrometer were used to determine their chemical components and main functional groups, respectively. The Folin-Ciocalteu and aluminium chloride techniques were utilized to assess the total flavonoid and phenolic levels of PSB. Following that, PSB has been incorporated into the coating mixture, which contains MSM, and its potential radical scavenging and antibacterial activities on lamb meat samples were determined after 10 days of 4 °C storage. PSB contains 2-Methyldecane, 2-Methylpiperidine, phenol, 2,4-bis (1,1-dimethyl ethyl), 5,10-Diethoxy-2,3,7,8- tetrahydro-1H,6H-dipyrrolo[1,2-a:1',2'-d] pyrazine, and Ergotaman-3',6',18-trione, 12'-hydroxy-2'-methyl-5'-(phenylmethyl)-, (5'alpha) as well as various organic acids with significant radical scavenging activity (84.60 ± 0.62 %) and antibacterial action toward Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus, and Listeria innocua as foodborne pathogens. The edible PSB-MSM coating effectively reduced microbial growth and increased meat shelf life (> 10 days). When PSB solutions were added to the edible coating, the moisture content, pH value, and hardness of the samples were also more successfully maintained (P < 0.05). The PSB-MSM coating inhibited lipid oxidation in meat samples considerably and diminished the formation of primary as well as secondary oxidation intermediates (P < 0.05). Additionally, when MSM + 10 % PSB edible coating was utilized, the sensory properties of the samples were maintained more well during preservation. As a significance, the use of edible coatings based on PSB and MSM is efficient in decreasing microbiological and chemical degradation in lamb meat during preservation.

Biology, taxonomy, genetics, and management of Zymoseptoria tritici: the causal agent of wheat leaf blotch

Septoria tritici blotch or Septoria leaf blotch has been used for long time, but leaf blotch is a correct disease name. Moreover, Lb resistant gene is the correct name, but, not Stb gene. It has sexual and asexual parts on the mycelia, known as heterothallic fungi. Its pathogenic diversity ranged from 40% to 93% and has produced a wide variety of AvrLb6 haplotypes. M. graminicola has a plasmogamy and karyogamy sexual process. The pathogen can use macropycnidiospores, micropycnidiospores, and pycnidia vegetative growths for infection and overwintering. Synthetic M3, Kavkaz-K4500, Synthetic 6×, and TE9111 wheat genotypes have horizontal resistance. Avirulence (Avr) genes in Z. tritici and their matching wheat (R) genes indicate gene for gene mechanisms of resistance. Twenty-two R genes (vertical resistance) have been identified. In both horizontal and vertical resistance, different Lb genes have been broken down due to new Z.tritici virulent gene and currently Lb19 resistant gene is being recommended. Mixing of resistant and susceptible cultivars is also the most effective management strategy. Moreover, different cultural practices and biological control have been proposed. Lastly, different fungicides are also available. However, in developing countries cultivar mixture, isolates diversity, biological control, and epidemic studies have been greatly missed.

Extraction and characterization of bioactive secondary metabolites from lactic acid bacteria and evaluating their antifungal and antiaflatoxigenic activity

Aflatoxins are toxic carcinogens and mutagens formed by some moulds, specifically Aspergillus spp. Therefore, this study aimed to extract and identify bioactive secondary metabolites from Lactobacillus species, to evaluate their efficacy in reducing fungal growth and aflatoxin production and to investigate their toxicity. The bioactive secondary metabolites of Lactobacillus species showed variable degrees of antifungal activity, whereas L. rhamnosus ethyl acetate extract No. 5 exhibited the highest antifungal activity and, thus, was selected for further identification studies. Data revealed that L. rhamnosus ethyl acetate extract No. 5 produced various organic acids, volatile organic compounds and polyphenols, displayed antifungal activity against A. flavus, and triggered morphological changes in fungal conidiophores and conidiospores. L. rhamnosus ethyl acetate extract No. 5 at a 9 mg/mL concentration reduced AFB₁ production by 99.98%. When the effect of L. rhamnosus ethyl acetate extract No. 5 on brine shrimp mortality was studied, the extract attained a 100% mortality at a concentration of 400 µg/mL, with an IC₅₀ of 230 µg/mL. Meanwhile, a mouse bioassay was performed to assess the toxicity of L. rhamnosus ethyl acetate extract No. 5, whereas there were no harmful effects or symptoms in mice injected with L. rhamnosus ethyl acetate extract at concentrations of 1, 3, 5, 7, and 9 mg/kg body weight.

Probiotics and their postbiotics for the control of opportunistic fungal pathogens: A review

During past twenty years the opportunistic fungal infections have been emerging, causing morbidity and mortality. The fungi belonging to Aspergillus, Mucor, Rhizopus, Candida, Fusarium, Penicillium, Dermatophytes and others cause severe opportunistic fungal infections. Among these Aspergillus and Candida spp cause majority of the diseases. The continuum of fungal infections will prolong to progress in the surroundings of the growing inhabitants of immunocompromised individuals. Presently many chemical-based drugs were used as prophylactic and therapeutic agents. Prolonged usage of antibiotics may lead to some severe effect on the human health. Also, one of the major threats is that the fungal pathogens are becoming the drug resistant. There are many physical, chemical, and mechanical methods to prevent the contamination or to control the disease. Owing to the limitations that are observed in such methods, biological methods are gaining more interest because of the use of natural products which have comparatively less side effects and environment friendly. In recent years, research on the possible use of natural products such as probiotics for clinical use is gaining importance. Probiotics, one of the well studied biological products, are safe upon consumption and are explored to treat various fungal infections. The antifungal potency of major groups of probiotic cultures such as Lactobacillus spp, Leuconostoc spp, Saccharomyces etc. and their metabolic byproducts which act as postbiotics like organic acids, short chain fatty acids, bacteriocin like metabolites, Hydrogen peroxide, cyclic dipeptides etc. to inhibit these opportunistic fungal pathogens have been discussed here.

Assessing the protection mechanisms against Enterobacter aerogenes by analyzing aggregation, adherence, antagonistic activity, and safety properties of potentially probiotic strain Lactobacillus brevis G145

The aim of this study was to evaluate the probiotic potential of Lactobacillus brevis G145 isolated from traditional Khiki cheese, analyzing pH and bile resistance, physicochemical properties of the strain (hydrophobicity, auto- and co-aggregation), cholesterol removal, hydroxyl radical scavenging activity, adhesion ability to Caco-2 cells monolayer, and adhesion competition on Enterobacter aerogenes (competition, inhibition and replacement assays). Also, DNase, haemolytic activity, biogenic amine production and antibiotic susceptibility was investigated. L. brevis G145 was resistant to acidic pHs, bile salts, and simulated gastrointestinal conditions, and showed remarkable cell surface hydrophobicity (49.56%), co-aggregation (28.90%), auto-aggregation (34.10%), adhesion (9.40%), cholesterol removal (45.50%), and antioxidant (52.19%) properties. According to the results of well diffusion agar and disc diffusion agar tests, the highest and lowest inhibition zones were accounted for Staphylococcus aureus and Enterobacter aerogenes, respectively. The isolate did not show haemolytic, DNAse, and biogenic amine production properties. It was sensitive to antibiotics erythromycin, ciprofloxacin, and chloramphenicol, and semi-sensitive to imipenem, ampicillin, nalidixic acid, and nitrofurantoin. According to the findings of probiotic tests L. brevis G145 can be used as a in the food industry.

Effects of Fermented Artemisia annua L. and Salicornia herbacea L. on Inhibition of Obesity In Vitro and In Mice

Plant extracts including secondary metabolites have anti-inflammatory and anti-obesity activities. This study was conducted to investigate the anti-obesity properties of fermented Artemisia annua (AW) and Salicornia herbacea (GW) in vitro and in mice. The metabolite profiling of AW and GW extracts was performed using UHPLC-LTQ-Orbitrap-MS/MS, and gene expression was analyzed using real-time PCR for adipocyte difference factors. The anti-obesity effects in mice were measured using serum AST, ALT, glucose, TG, and cholesterol levels. Metabolites of the plant extracts after fermentation showed distinct differences with increasing anti-obesity active substances. The efficacy of inhibitory differentiation adipogenesis of 3T3-L1 adipocytes was better for GW than AW in a concentration-dependent manner. RT-PCR showed that the GW extract significantly reduced the expression of genes involved in adipocyte differentiation and fat accumulation (C/EBPα, PPARγ, and Fas). In C57BL/6 mice fed the HFD, the group supplemented with AW and GW showed reduced liver weight, NAS value, and fatty liver by suppressing liver fat accumulation. The GW group significantly reduced ALT, blood glucose, TG, total cholesterol, and LDL-cholesterol. This study displayed significant metabolite changes through biotransformation in vitro and the increasing anti-obesity effects of GW and AW in mice. GW may be applicable as functional additives for the prevention and treatment of obesity.

Manufacture of a Potential Antifungal Ingredient Using Lactic Acid Bacteria from Dry-Cured Sausages

The growing interest in functional foods has fueled the hunt for novel lactic acid bacteria (LAB) found in natural sources such as fermented foods. Thus, the aims of this study were to isolate, identify, characterize, and quantify LAB’s antifungal activity and formulate an ingredient for meat product applications. The overlay method performed a logical initial screening by assessing isolated bacteria’s antifungal activity in vitro. Next, the antifungal activity of the fermented bacteria-free supernatants (BFS) was evaluated by agar diffusion assay against six toxigenic fungi. Subsequently, the antifungal activity of the most antifungal BFS was quantified using the microdilution method in 96-well microplates. The meat broth that showed higher antifungal activity was selected to elaborate on an ingredient to be applied to meat products. Finally, antifungal compounds such as organic acids, phenolic acids, and volatile organic compounds were identified in the chosen-fermented meat broth. The most promising biological candidates belonged to the Lactiplantibacillus plantarum and Pediococcus pentosaceus. P. pentosaceus C15 distinguished from other bacteria by the production of antifungal compounds such as nonanoic acid and phenyl ethyl alcohol, as well as the higher production of lactic and acetic acid.

The potential of lactic acid bacteria in mediating the control of plant diseases and plant growth stimulation in crop production - A mini review

The microbial diseases cause significant damage in agriculture, resulting in major yield and quality losses. To control microbiological damage and promote plant growth, a number of chemical control agents such as pesticides, herbicides, and insecticides are available. However, the rising prevalence of chemical control agents has led to unintended consequences for agricultural quality, environmental devastation, and human health. Chemical agents are not naturally broken down by microbes and can be found in the soil and environment long after natural decomposition has occurred. As an alternative to chemical agents, biocontrol agents are employed to manage phytopathogens. Interest in lactic acid bacteria (LAB) research as another class of potentially useful bacteria against phytopathogens has increased in recent years. Due to the high level of biosafety, they possess and the processes they employ to stimulate plant growth, LAB is increasingly being recognized as a viable option. This paper will review the available information on the antagonistic and plant-promoting capabilities of LAB and its mechanisms of action as well as its limitation as BCA. This review aimed at underlining the benefits and inputs from LAB as potential alternatives to chemical usage in sustaining crop productivity.

Antifungal activity of potential probiotic Limosilactobacillus fermentum strains and their role against toxigenic aflatoxin-producing aspergilli

Two major aflatoxin-producing strains are Aspergillus flavus and Aspergillus niger. Probiotic bacteria have been identified as a potential means to fight aspergilli and reduce the availability of aflatoxin (AFs) as well as other food contaminants. In this study, the potential of ABRIIFBI-6 and ABRIIFBI-7 strains to inhibit the growth of aspergilli was investigated. Both strains survived in the simulated gastrointestinal conditions and inhibited the growth of Aspergillus significantly. Auto-aggregation ranged from 67.4 ± 1.9 for ABRIIFBI-6 to 75.8 ± 2.3% for ABRIIFBI-7, and hydrophobicity ranged from 57.3 ± 1.6 to 61.2 ± 1.4% for ABRIIFBI-6 and ranged from 51.2 ± 1.4 to 55.4 ± 1.8% for ABRIIFBI-7. The ranges of coaggregation with Staphylococcus aureus were 51.3 ± 1.7 and 52.4 ± 1.8% for ABRIIFBI-6 and ABRIIFBI-7, respectively, while coaggregation with Bacillus cereus was 57.9 ± 2.1 and 49.3 ± 1.9% for ABRIIFBI-6 and ABRIIFBI-7, respectively. Both strains indicated remarkable sensitivity to clinical antibiotics. According to the analysis of the identified potential probiotics, the findings of this study could significantly contribute to the understanding of the probiotic potential of LAB in dairy products in order to access their probiotic characterization for use as biocontrol of aflatoxin-producing species.

Strategies for the Development of Bioprotective Cultures in Food Preservation

Consumers worldwide are increasingly demanding food with fewer ingredients, preferably without chemical additives. The trend called "Clean Label" has stimulated the development and commercialization of new types of bioprotective bacterial cultures. These bacteria are not considered new, and several cultures have been available on the market. Additionally, new bioprotective bacteria are being identified to service the clean label trend, extend the shelf life, and, mainly, improve the food safety of food. In this context, the lactic acid bacteria (LAB) have been extensively prospected as a bioprotective culture, as they have a long history in food production and their antimicrobial activity against spoilage and pathogenic microorganisms is well established. However, to make LAB cultures available in the market is not that easy, the strains should be characterized phenotypically and genotypically, and studies of safety and technological application are necessary to validate their bioprotection performance. Thus, this review presents information on the bioprotection mechanisms developed by LAB in foods and describes the main strategies used to identify and characterize bioprotective LAB with potential application in the food industry.

Current approaches on the roles of lactic acid bacteria in crop silage

Lactic acid bacteria (LAB) play pivotal roles in the preservation and fermentation of forage crops in spontaneous or inoculated silages. Highlights of silage LAB over the past decades include the discovery of the roles of LAB in silage bacterial communities and metabolism and the exploration of functional properties. The present article reviews published literature on the effects of LAB on the succession, structure, and functions of silage microbial communities involved in fermentation. Furthermore, the utility of functional LAB in silage preparation including feruloyl esterase-producing LAB, antimicrobial LAB, lactic acid bacteria with high antioxidant potential, pesticide-degrading LAB, lactic acid bacteria producing 1,2-propanediol, and low-temperature-tolerant LAB have been described. Compared with conventional LAB, functional LAB produce different effects; specifically, they positively affect animal performance, health, and product quality, among others. In addition, the metabolic profiles of ensiled forages show that plentiful probiotic metabolites with but not limited to antimicrobial, antioxidant, aromatic, and anti-inflammatory properties are observed in silage. Collectively, the current knowledge on the roles of LAB in crop silage indicates there are great opportunities to develop silage not only as a fermented feed but also as a vehicle of delivery of probiotic substances for animal health and welfare in the future.

Antifungal activity of protective cultures against the yogurt drink-specific spoilage yeasts

Fungal agents emerged as post-pasteurization contamination are responsible for the spoilage in yogurt drink. In this work, the antifungal effects of some lactic acid bacteria (LAB) on the spoilage yeasts isolated from yogurt drink (Doogh) were evaluated. First, the microbial growth in the yogurt drink samples during the storage time was investigated, and the isolated microorganisms were identified using biochemical methods and sequencing of the specific amplicons. Yeasts (3-7 log CFU ml^-1 ) were found to be the most abundant microorganisms (specific spoilage organisms) in several samples. Using the amplification technique of rDNA by ITS1 and ITS4 primers, the dominant yeasts were identified as Pichia kudriavzevii, Kluyveromyces marxianus, and Candida parapsilosis. Then, the antimicrobial activity of 37 strains of LAB against the isolated yeasts was studied using broth microdilution. Eventually, the strains of Lacticplantibacillus plantarum (245, 24, P6, and P7), Lactiplantibacillus pentosus (20), and Levilactobacillus brevis (30) exhibited significant antifungal activity. In the most effective impacts, lag times of C. parapsilosis, K. marxianus, and P. kudriavzevii were increased by almost 12-19 h, 12-19 h, and 2-6 h, respectively, while the area under the growth curve for these yeasts was reduced to lower than 40%, near 16%, and approximately 67%, in the order given. Overall, these bacteria showed high potential as the substituents for chemical preservatives in yogurt drinks. PRACTICAL APPLICATION: Spoilage yeasts were isolated from yogurt drink and identified by molecular method. Isolated yeasts belonged to Pichia, Kluyveromyces, and Candida genera. Inhibitory effects of 37 strains were evaluated against the spoilage yeasts. Cell-free supernatant was used against the isolated fungi in microdilution method. Several LAB strains showed a significant antimicrobial activity.

Biotechnological and Medical Aspects of Lactic Acid Bacteria Used for Plant Protection: A Comprehensive Review

The use of chemical pesticides in agriculture goes hand in hand with some crucial problems. These problems include environmental deterioration and human health complications. To eliminate the problems accompanying chemical pesticides, biological alternatives should be considered. These developments spark interest in many environmental fields, including agriculture. In this review, antifungal compounds produced by lactic acid bacteria (LABs) are considered. It summarizes the worldwide distribution of pesticides and the effect of pesticides on human health and goes into detail about LAB species, their growth, fermentation, and their antifungal compounds. Additionally, interactions between LABs with mycotoxins and plants are discussed.

Antifungal activity of lactic acid bacteria and their application in food biopreservation

Lactic acid bacteria (LAB) are ubiquitous bacteria associated with spontaneous lactic fermentation of vegetables, dairy and meat products. They are generally recognized as safe (GRAS), and they are involved in transformation of probiotic lacto-fermented foods, highly desired for their nutraceutical properties. The antifungal activity is one of the exciting properties of LAB, because of its possible application in food bio-preservation, as alternative to chemical preservatives. Many recent research works have been developed on antifungal activity of LAB, and they demonstrate their capacity to produce various antifungal compounds, (i.e. organic acids, PLA, proteinaceous compounds, peptides, cyclic dipeptides, fatty acids, and other compounds), of different properties (hydrophilic, hydrophobic and amphiphilic). The effectiveness of LAB in controlling spoilage and pathogenic fungi, demonstrated in different agricultural and food products, can be due to the synergistic effect between their antifungal compounds of different properties; where the amphiphilic-compounds allow the contact between the target microbial cell (hydrophilic compartment) and antifungal hydrophobic-compounds. Further studies on the interaction between compounds of these three properties are to de be developed, in order to highlight more their mechanism of action, and make LAB more profitable in improving shelf life and nutraceutical properties of foods.

Effects of Bifidobacteria Fermentation on Physico-Chemical, Thermal and Structural Properties of Wheat Starch

Lactic acid bacteria have been considered to be a very important species during sourdough fermentation. In order to explore the effects of bifidobacteria fermentation on thermal, physico-chemical and structural properties of wheat starch during dough fermentation, starch granules were separated from the fermented dough at different fermentation times, including 0 h, 2 h, 6 h, 9 h and 12 h. The results showed that the morphology of starch granules was destroyed gradually as the fermentation time increased, which appeared as erosion and rupture. With the increase in fermentation time, the solubility showed a significant increase, which changed from 8.51% (0 h) to 9.80% (12 h), and the swelling power was also increased from 9.31% (0 h) to 10.54% (12 h). As for the gelatinization property, the enthalpy was increased from 6.77 J/g (0 h) to 7.56 J/g (12 h), indicating a more stable thermal property of fermented starch, especially for the longer fermentation. The setback value was decreased with short fermentation time, indicating that the starch with a longer fermentation time was difficult to retrograde. The hardness of the gel texture was decreased significantly from 50.11 g to 38.66 g after fermentation for 12 h. The results show that bifidobacteria fermentation is an effective biological modification method of wheat starch for further applications.

Lactic Acid Bacteria as Biocontrol Agents against Potato (Solanum tuberosum L.) Pathogens

Biological control offers an alternative to chemical pesticides, which are inconsistent with the global trend of “going green”. Biological control includes various approaches, from natural predators to biologically produced molecules. This article focuses on the selection of lactic acid bacteria (LAB) as biological control agents against potato pathogens. The scope included evaluating the antimicrobial activity of 100 LAB strains against ten phytopatogens (Pectobacterium carotovorum, Streptomyces scabiei, Fusarium oxysporum, Fusarium sambucinum, Alternaria solani, Alternaria, tenuissima, Alternaria alternata, Phoma exigua, Rhizoctonia solani, Colletotrichum coccodes) by cross-streak plate method. HPLC determined the metabolic profiles for the most active LAB strains, and lactic acid, acetic acid, propionic acid and ethanol were found in the largest quantities. The strain Lactiplantibacillus plantarum KB2 LAB 03 was finally selected and cultured on supplemented acid whey. After the selection in laboratory tests, the strain KB2 LAB 03 was assessed in situ on seed potatoes against phytopathogens. The test showed a 40–90% reduction of eight potato pathogens infestation; only F. sambucinum and F. oxysporum were not inhibited at all. L. plantarum KB2 LAB 03 was proposed as the potential biocontrol agent for the potato protection against phytopathogens.

Lactic Acid Bacteria in Raw-Milk Cheeses: From Starter Cultures to Probiotic Functions

Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid acidification of milk or as secondary microbiota that play an important role during cheese ripening. The enzymes produced by such dynamic LAB communities in raw milk are crucial, since they support proteolysis and lipolysis as chief drivers of flavor and texture of cheese. Recently, several LAB species have been characterized and used as probiotics that successfully promote human health. This review highlights the latest trends encompassing LAB acting in traditional raw milk cheeses (from cow, sheep, and goat milk), and their potential as probiotics and producers of bioactive compounds with health-promoting effects.

Lactic Acid Bacteria as Potential Biocontrol Agents for Fusarium Head Blight Disease of Spring Barley

Fusarium head blight (FHB) is a devastating disease encountered by spring-grown barley. Traditionally, synthetic chemicals have been used to control this disease on small grain cereals. A move toward biological control agents as part of sustainable agriculture is pertinent due to the evolutionary mechanisms employed by fungal diseases to circumvent current protection strategies. This study evaluated the effect of six lactic acid bacteria isolates on the development of FHB under in vitro and glasshouse conditions. The relative expression of Fusarium marker genes and transcription factors under Fusarium infection was examined. Dual-culture assays observed inhibition zones of up to 10 and 17% of total plate area for L. amylovorus FST 2.11 and L. brevis R2Δ, respectively. Detached leaf assays validated the antifungal activity and showed the potential of all test isolates to significantly inhibit sporulation of Fusarium culmorum and Fusarium graminearum strains. Spray inoculation of lactic acid bacteria to barley spikelets prior to Fusarium spore application significantly reduced disease severity for five candidates (P < 0.05) under glasshouse conditions. Mycotoxin analysis revealed the ability of L. amylovorus DSM20552 to significantly reduce deoxynivalenol content in spikelets (P < 0.05). A preliminary gene expression study showed the positive influence of lactic acid bacteria on the expression of important defense-related marker genes and transcription factors upon FHB. These results indicate the potential of lactic acid bacteria to be included as part of an integrated pest management strategy for the management of FHB disease. This strategy will reduce FHB severity and deoxynivalenol (DON) contamination of spring barley, leading to high acceptance in the grain market.

Antifungal Potential of Bacillus velezensis CE 100 for the Control of Different Colletotrichum Species through Isolation of Active Dipeptide, Cyclo-(D-phenylalanyl-D-prolyl)

Colletotrichum species are important fungal pathogens causing anthracnose of tropical and subtropical fruit and vegetable crops. Dual culture assay indicated that Bacillus velezensis CE 100 was a strong antagonist against C. acutatum, C. coccodes, C. dematium, and C. gloeosporioides. The volatile organic compounds produced by B. velezensis CE 100 affected mycelial growth of Colletotrichum species tested in our study and caused twisted hyphal structures of all these fungal species. Chloroform crude compounds of B. velezensis CE 100 inhibited four Colletotrichum species in a concentration-dependent manner and induced severe damage in hyphal morphology of these fungal pathogens, including swelling, bulging, and multiple branching. Moreover, the active cyclic dipeptide, cyclo-(D-phenylalanyl-D-prolyl), was isolated from chloroform crude extract and identified by nuclear magnetic resonance (NMR) and mass spectrometry. The inhibitory effect of cyclo-(D-phenylalanyl-D-prolyl) on conidial germination of C. gloeosporioides occurred in a concentration-dependent manner. The conidial germination rate was completely inhibited by a concentration of 3 mg/mL of cyclo-(D-phenylalanyl-D-prolyl). Scanning electron micrographs revealed that the exposure to cyclic dipeptide resulted in seriously deformed hyphae and conidia with shriveled surfaces in dipeptide-treated C. gloeosporioides. Therefore, active dipeptide-producing B. velezensis CE 100 is a promising biocontrol agent for Colletotrichum species causing anthracnose.

Characterization of antimicrobial compounds obtained from the potential probiotic Lactiplantibacillus plantarum S61 and their application as a biopreservative agent

This work aimed to characterize the antimicrobial compounds obtained from the potential probiotic Lactiplantibacillus plantarum S61, isolated from traditional fermented green olive, involved in their activity against fungi and bacteria responsible for food spoilage and poisonings. Their application as a biopreservative agent was also investigated. The culture of L. plantarum S61 showed substantial antifungal and antibacterial activity against yeasts (Rhodotorula glutinis and Candida pelliculosa), molds (Penicillium digitatum, Aspergillus niger, Fusarium oxysporum, and Rhizopus oryzae), and pathogenic bacteria (Listeria monocytogenes ATCC 19,117, Salmonella enterica subsp. enterica ATCC 14,028, Staphylococcus aureus subsp. aureus ATCC 6538, Pseudomonas aeruginosa ATCC 49,189), with inhibition zones > 10 mm. Likewise, the cell-free supernatant (CFS) of L. plantarum S61 showed an essential inhibitory effect against fungi and bacteria, with inhibition diameters of 12.25-22.05 mm and 16.95-17.25 mm, respectively. The CFS inhibited molds' biomass and mycelium growth, with inhibition ranges of 63.18-83.64% and 22.57-38.93%, respectively. The antifungal activity of the CFS was stable during 4 weeks of storage at 25 °C, while it gradually decreased during storage at 4 °C. Several antimicrobial compounds were evidenced in the CFS of L. plantarum S61, including organic acids, ethanol, hydrogen peroxide, diacetyl, proteins, and fatty acids. The protein fraction, purified by reversed-phase high-performance liquid chromatography (RP-HPLC), demonstrated important antifungal activity, in relation to the fraction with molecular weight between 2 and 6 kDa. L. plantarum S61 and its CFS, tested in apple and orange fruit biopreservation, demonstrated their protective effect against P. digitatum spoilage. The CFS exhibited effectiveness in reducing Salmonella enterica subsp. enterica ATCC 14,028 in apple juice. L. plantarum S61 and/or its bioactive compounds CFS represent a promising strategy for biocontrol against pathogens and spoilage microorganisms in the agro-industry.

Textural and Functional Properties of Skimmed and Whole Milk Fermented by Novel Lactiplantibacillus plantarum AG10 Strain Isolated from Silage

Milk fermentation by lactic acid bacteria both enhances its nutritional value and provides probiotic strains to correct the intestinal microflora. Here, we show the comparative analysis of milk fermented with the new strain, Lactiplantibacillus plantarum AG10, isolated from silage and the industrial strain Lactobacillus delbrukii subs. bulgaricus. While the milk acidification during fermentation with L. plantarum AG10 was lower compared with L. bulgaricus, milk fermented with L. plantarum AG10 after a 14-day storage period retained a high level of viable cells and was characterized by an increased content of exopolysaccharides and higher viscosity. The increased EPS production led to clot formation with higher density on microphotographs and increased firmness and cohesiveness of the product compared with L. bulgaricus-fermented milk. Furthermore, the L. plantarum AG10-fermented milk exhibited increased radical-scavenging activity assuming lower fat oxidation during storage. Taken together, these data suggest that L. plantarum AG10 seems to be a promising starter culture for dairy products with lowered levels of lactic acid, which is important for people with increased gastric acid formation.

Purification and characterization of antifungal lipopeptide produced by Bacillus velezensis isolated from raw honey

Raw honey contains a diverse microbiota originating from honeybees, plants, and soil. Some gram-positive bacteria isolated from raw honey are known for their ability to produce secondary metabolites that have the potential to be exploited as antimicrobial agents. Currently, there is a high demand for natural, broad-spectrum, and eco-friendly bio-fungicides in the food industry. Naturally occurring antifungal products from food-isolated bacteria are ideal candidates for agricultural applications. To obtain novel antifungals from natural sources, we isolated bacteria from raw clover and orange blossom honey to evaluate their antifungal-producing potential. Two Bacillus velezensis isolates showed strong antifungal activity against food-isolated fungal strains. Antifungal compound production was optimized by adjusting the growth conditions of these bacterial isolates. Extracellular proteinaceous compounds were purified via ammonium sulfate precipitation, solid phase extraction, and RP-HPLC. Antifungal activity of purified products was confirmed by deferred overlay inhibition assay. Mass spectrometry (MS) was performed to determine the molecular weight of the isolated compounds. Whole genome sequencing (WGS) was conducted to predict secondary metabolite gene clusters encoded by the two antifungal-producing strains. Using MS and WGS data, we determined that the main antifungal compound produced by these two Bacillus velezensis isolates was iturin A, a lipopeptide exhibiting broad spectrum antifungal activity.

Panchgavya: A precious gift to humankind

Panchgavya represents milk, urine, dung, ghee, and curd, derived from cow and serves irreplaceable medicinal importance in Ayurveda and traditional Indian clinical practices. In Ayurveda,Panchgavya treatment is termed as 'Cowpathy'. In India, the cow is worshipped as a god called 'Gaumata,' indicating its nourishing nature like a mother. Ayurveda recommends Panchagavya to treat diseases of multiple systems, including severe conditions, with almost no side-effects. It can help build a healthy population, alternative sources of energy, complete nutritional requirements, eradicate poverty, pollution-free environment, organic farming, etc. Panchgavya can also give back to mother nature by promoting soil fertility, earthworm production, protecting crops from bacterial and fungal infections, etc. Scientific efforts shall be taken to build evidence for the clinical application of Cowpathy. The present review aims to summarize the health and medicinal benefits of Panchgavya.

Antagonistic Effects of Conjugated Linoleic Acids of Lactobacillus casei against Foodborne Enterohemorrhagic Escherichia coli

ABSTRACT

Probiotics in fermented foods or commercially available supplements benefit the host by providing metabolites and peptides. The production of these metabolites varies with the available substrates or prebiotics present in the system and their concentration. In this study, 0.5% peanut flour (PF) was used to stimulate the growth and production of metabolites of wild-type Lactobacillus casei (LCwt) and compare with an engineered L. casei (LCCLA) capable of converting a higher amount of conjugated linoleic acid (CLA). The total extracellular metabolites present in the cell-free cultural supernatant (CFCS) of LCwt (without peanut), LCwt+PF (with peanut), and LCCLA were collected after 24 and 48 h of incubation, and their antagonistic activities against enterohemorrhagic Escherichia coli (EHEC EDL933) growth and pathogenesis were evaluated. All collected metabolites exhibited varying efficiency in restraining EHEC EDL933 growth, whereas supplementing a low concentration of CLA to the 48-h CFCS from LCwt showed augmented antagonism toward EHEC EDL933. A downregulation of key virulence genes was observed from metabolites collected at the 48-h time point. These observations indicate that the presence of metabolites in CFCSs-including CLA, which is produced by Lactobacillus and was identified by gas chromatography-mass spectrometry-plays a critical role. This study demonstrates the potential applicability of Lactobacillus-originated CLA in the prevention of EHEC EDL933-mediated illnesses.

HIGHLIGHTS

The Potential of Fatty Acids and Their Derivatives as Antifungal Agents: A Review

Fungal contamination presents several problems: in humans, health issues arise from infections with opportunistic filamentous fungi and yeast, while in food, fungi cause spoilage and, in particular, in the case of mycotoxigenic fungi, can cause serious health issues. Several types of fatty acids and their derivatives, oxylipins, have been found to have inhibitory effect towards fungal growth and the production of mycotoxins. The use of fatty acids as antifungals could fulfil consumer’s requests of more natural and environmentally friendly compounds, while being less likely to promote fungal resistance. In addition, due to their nature, fatty acids are easily used as food additives. In this work, we review the most relevant and recent studies on the antifungal ability of fatty acids. We focused on saturated fatty acids, unsaturated fatty acids, and oxylipins, their different impact on fungal inhibition, their proposed modes of action, and their ability to impair mycotoxin production. Applications of fatty acids as antifungals and their limitations are also addressed.

Ensiling Grape Pomace With and Without Addition of a Lactiplantibacillus plantarum Strain: Effect on Polyphenols and Microbiological Characteristics, in vitro Nutrient Apparent Digestibility, and Gas Emission

The present study investigated the effects of different grape pomace storage techniques on the effectiveness as feed on in vitro ruminant digestion efficiency. Grape pomace from an autochthonous red grape variety (cv Nero di Troia) was used as fresh (GP) or ensiled, both without additives (SIL) and with the addition of a bacterial strain, Lactiplantibacillus plantarum 5BG (SIL+). All the different storage treatments were subject to chemical and microbiological evaluation, as well as in vitro digestibility, and gas production. Microbiological data revealed the good quality of grape pomace and silages due to the lactic acid bacteria populations and low presence, or absence, of undesirable microorganisms. The addition of L. plantarum 5BG influenced the chemical characteristics of the silage (SIL+). Ensiling technique deeply changed the polyphenolic composition, reducing anthocyanins, flavonols, and flavanols (condensed tannins precursors), particularly when L. plantarum 5BG was added. Antioxidant capacity was reduced by ensiling, in correlation with the polyphenolic content decrease. The oxygen radical absorbance capacity (ORAC) value of SIL+ was the lowest (P < 0.01) and its total phenol content was lower than SIL (P < 0.01). No statistical differences were observed between GP, SIL, and SIL+ on the antioxidant capacity by TEAC assay (P > 0.05). Ensiling did not affect the grape pomace nutrient profile, except for the reduction in NFC content. Apparent in vitro digestibility showed how ensiling increased dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), crude protein (CP), ether extract (EE), and non-fiber carbohydrates (NFC) disappearance (P < 0.01), particularly with the L. plantarum 5BG inoculation. Moreover, SIL+ showed the lowest propionic acid (P < 0.05) and the highest methane (P < 0.01), butyric acid (P < 0.01), and nitrogen (P < 0.05) in vitro production. Ensiling GP resulted in a better in vitro digestibility, particularly if L. plantarum 5BG strain is added, probably due to the reduction of flavanols and their lower microbial activity inhibition.

A Comprehensive Review on Bio-Preservation of Bread: An Approach to Adopt Wholesome Strategies

Bread is a food that is commonly recognized as a very convenient type of food, but it is also easily prone to microbial attack. As a result of bread spoilage, a significant economic loss occurs to both consumers and producers. For years, the bakery industry has sought to identify treatments that make bread safe and with an extended shelf-life to address this economic and safety concern, including replacing harmful chemical preservatives. New frontiers, on the other hand, have recently been explored. Alternative methods of bread preservation, such as microbial fermentation, utilization of plant and animal derivatives, nanofibers, and other innovative technologies, have yielded promising results. This review summarizes numerous research findings regarding the bio-preservation of bread and suggests potential applications of these techniques. Among these techniques, microbial fermentation using lactic acid bacteria strains and yeast has drawn significant interest nowadays because of their outstanding antifungal activity and shelf-life extending capacity. For example, bread slices with Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5 inhibited fungal development for up to 21 days with the lowest contamination score. Moreover, various essential oils and plant extracts, such as lemongrass oil and garlic extracts, demonstrated promising results in reducing fungal growth on bread and other bakery products. In addition, different emerging bio-preservation strategies such as the utilization of whey, nanofibers, active packaging, and modified atmospheric packaging have gained considerable interest in recent days.

Characteristic properties of spray-drying Bifidobacterium adolescentis microcapsules with biosurfactant

The surfactants used for emulsion is one of the best techniques for microencapsulation of lactic acid bacteria (LAB) since it is economical. The biosurfactants have many advantages such as lower toxicity, higher biodegradability. In this study, microcapsules were prepared via spray drying using Bifidobacterium adolescentis species cultured in soy milk extract with biosurfactant prepared using Alcaligenes piechaudii CC-ESB2 to improve their powder properties. The soy milk was used to increase the health benefits instead of the milk. The optimum bacterial strain viability, water activity, and moisture content of the microcapsules were achieved at a spray dryer inlet/outlet temperature of 120/60°C. The composition of the carrier affects the particle size of the microcapsules. Using 90% maltodextrin (MD), 5% isomalto-oligosaccharide syrup (IMOS) and 5% biosurfactant as a carrier increased the viability of the LAB. Scanning electron microscope observations showed that the LAB microcapsules were able to effectively retain their completeness. Furthermore, microcapsules added with a biosurfactant prepared using A. piechaudii CC-ESB2 displayed significantly better flow properties than those without the surfactant and biosurfactant, which indicates that the biosurfactant assists in enhancing the powder properties of the microcapsules. It also has sufficient biological activity as a LAB product because the probiotics exceed 10⁶ CFU/mL The spray-dried abandoned supernatant with biosurfactant exhibited superior bacteriostasis, which suggests that the supernatant of B. adolescentis during microencapsulation not only retains its bacteriostatic effect under high spray drying temperatures, but also provides additional antibacterial effects for the microcapsules.

Antifungal Metabolites as Food Bio-Preservative: Innovation, Outlook, and Challenges

Perishable food spoilage caused by fungi is a major cause of discomfort for food producers. Food sensory abnormalities range from aesthetic degeneration to significant aroma, color, or consistency alterations due to this spoilage. Bio-preservation is the use of natural or controlled bacteria or antimicrobials to enhance the quality and safety of food. It has the ability to harmonize and rationalize the required safety requirements with conventional preservation methods and food production safety and quality demands. Even though synthetic preservatives could fix such issues, there is indeed a significant social need for "clean label" foods. As a result, consumers are now seeking foods that are healthier, less processed, and safer. The implementation of antifungal compounds has gotten a lot of attention in recent decades. As a result, the identification and characterization of such antifungal agents has made promising advances. The present state of information on antifungal molecules, their modes of activity, connections with specific target fungi varieties, and uses in food production systems are summarized in this review.

Bioprospecting Antimicrobials from Lactiplantibacillus plantarum: Key Factors Underlying Its Probiotic Action

Lactiplantibacillus plantarum (L. plantarum) is a well-studied and versatile species of lactobacilli. It is found in several niches, including human mucosal surfaces, and it is largely employed in the food industry and boasts a millenary tradition of safe use, sharing a long-lasting relationship with humans. L. plantarum is generally recognised as safe and exhibits a strong probiotic character, so that several strains are commercialised as health-promoting supplements and functional food products. For these reasons, L. plantarum represents a valuable model to gain insight into the nature and mechanisms of antimicrobials as key factors underlying the probiotic action of health-promoting microbes. Probiotic antimicrobials can inhibit the growth of pathogens in the gut ensuring the intestinal homeostasis and contributing to the host health. Furthermore, they may be attractive alternatives to conventional antibiotics, holding potential in several biomedical applications. The aim of this review is to investigate the most relevant papers published in the last ten years, bioprospecting the antimicrobial activity of characterised probiotic L. plantarum strains. Specifically, it focuses on the different chemical nature, the action spectra and the mechanisms underlying the bioactivity of their antibacterial and antiviral agents. Emerging trends in postbiotics, some in vivo applications of L. plantarum antimicrobials, including strengths and limitations of their therapeutic potential, are addressed and discussed.